The prior art includes many types of windows which are employed to bring light into a building. One type of window known in the prior art is a double-hung window. Such a window typically employs two vertically movable sash assemblies, each carrying its own pane of glass, which are movable, typically, vertically within the frame.
Opposed, inwardly facing lateral portions of the frame are typically provided with a balance tube which includes appropriate structure to render the window sashes more safe. Balance mechanisms are employed within the balance tube in order to deter undesirable, unintended slamming of a sash such that injury could result.
It is also desirable, however, that the sashes be able to be tilted inward or removed for cleaning of the glass portions of the sash assemblies. Various mechanisms have been employed to release a sash from a position which it is intended to occupy within the frame. Typically, a sash is desired to be located at a position along an axis, generally perpendicular to a plane defined by the frame, for sliding movement along that position. Various types of structures have been utilized to effect maintenance of a sash in the desired position yet allow it to be tilted inward or removed for cleaning. One such structure utilizes a pair of laterally extending latch mechanisms carried by the sash. The latch mechanisms move linearly along an axis through the sash and into the frame. One latch mechanism extends laterally on one side of the sash and a second latch mechanism extends laterally on the other side of the sash. When it is desired to remove a sash, the sash is moved to an intended vertical release location, and the person removing the sash releases one latch with one hand and the other latch with the other hand. The sash is then tilted or slid out of its normal position and removed from the frame for cleaning. Such a structure has a number of drawbacks. One is that the person removing the window sash needs full availability of both hands to effect release of the latches. Attempts have been made to solve this problem by designing a unitary assembly for concurrently releasing both latches (that is, for simultaneously effecting retraction of the latches). While some measure of success has been achieved with these attempts, other problems still exist. For example, linearly moving latches typically do not provide fully adequate definition of structure for sliding of a sash along an intended track and adequate resistance to pressures which might tend to dislodge a sash from the window frame. One reason for the inadequate resistance to dislodgement is the relatively small cross-section of a latch mechanism extending from the sash.
It is to these dictates and shortcomings of the prior art that the present invention is directed. It is a position maintenance mechanism which addresses these dictates and problems and provides solutions which make the invention a significant over prior art apparatuses.